size = int(input("请输入棋盘大大小："))
for i in range(size):
    for j in range(size):
        if i == 0 and j ==0:
            print("┍",end='')
        elif i == 0 and j == size - 1:
            print("┐",end='')
        elif i == size - 1 and j == 0:
            print("┖",end='')
        elif i == size - 1 and j == size - 1:
            print("┙",end='')
        elif j == 0:
            print("├",end='')
        elif i == size - 1:
            print("┷",end='')
        elif j == size - 1:
            print("┨",end='')
        elif i == 0:
            print("┯",end='')
        else:
            print("╉",end='')
    print('')